catching squid quickly and reliably can be a pain in the backside. you can see the guides still fishing for fresh squid hours after they've picked their clients up and often well past high tide cos they know how important they are to catching kings and jews. sometimes you can get a dozen in 10 minutes. sometimes you're messing about with jigs for hours...
the best advice i can give you is:
when it's rained you need to be nearer the fresh water - ie. outer harbour. if the water is dirty move on. you need kelp and ideally sandy spots. see the catch squid guide.
i've had my best results on the inside of south head or the outside of north head. lots of people persevere with middle head but it's only ever worked in fits and starts for me, plus i've tended lose too many jigs. obelisk bay is also touted, again never really produced for me.
if you can get yourself out of bed early (3am) then you'll be banking squid by fishing slinky malinky's drifting method under the spit. see how to section. then fish the morning high and catch some zeds on the sofa in the afternoon...
the alternative is to catch them the night before (or several nights before and freeze them) from any wharf that has kelp and bright light. obvious though it may sound, as with any type of fishing slowly building up a network of mates to call about where they are on any given weekend also pays dividends.